Dissatisfaction with the direction of the country, antipathy toward federal-government activism and opposition to the Democrats' health-care proposals drove the upset election of Republican senatorial candidate Scott Brown in Massachusetts, according to a post-election survey of state voters.

The poll by The Washington Post, the Henry J. Kaiser Family Foundation and Harvard University's School of Public Health underscores how significantly voter anger has turned toward Democrats in Washington and how dramatically the political landscape has shifted during President Obama's first year in office.

The findings do not provide a political portrait of the entire country in the opening weeks of the 2010 election year. But given that Massachusetts has been reliably Democratic in presidential elections, the results of Tuesday's special Senate election and the reasons voters sided with Brown over Democrat Martha Coakley speak to broader shifts that have taken place across the country over the past year.

These changes were echoed in national polling and helped elect Republican governors in Virginia and New Jersey in November. Democrats have been put squarely on the defensive. Obama and Democratic leaders are looking for ways to alter the political dynamics in the hope of heading off potentially sizable losses in their congressional majorities in this November's elections.

Sixty-three percent of Massachusetts special-election voters say the country is seriously off track, and Brown captured two-thirds of these voters on Tuesday. In November 2008, Obama won decisively among the more than 80 percent of Massachusetts voters seeing the country as off-course.

Nearly two-thirds of Brown's supporters say their vote was intended at least in part to express opposition to the Democratic agenda in Washington, but few say the senator-elect should simply work to stop it. Three-quarters of those who voted for Brown say they would like him to work with Democrats to get Republican ideas into legislation in general; nearly half say so specifically about health-care legislation.

When Obama was elected, 63 percent of Massachusetts voters said government should do more to solve problems, according to exit polling. In the new poll, that number slipped to 50 percent, with 47 percent saying government is doing too many things better left to businesses and individuals.

Like Obama, Coakley won the votes of more than 70 percent of those seeking government involvement, but the bigger pool of voters seeing government overreach helped Brown claim victory.

Health care topped jobs and the economy as the most important issue driving Massachusetts voters, but among voters for Brown, it was closely followed by the economy and jobs, and "the way Washington is working."

Overall, 43 percent of Massachusetts voters say they support the health-care proposals advanced by Obama and congressional Democrats; 48 percent oppose them. Among Brown's supporters, eight in 10 said they were opposed to the measures, 66 percent of them strongly so.

Sizable majorities of voters for Brown see the Democrats' plan, if passed, as making things worse for their families, the country and Massachusetts. Few Coakley voters see these negatives, and most of those backing her see clear benefits for the country if health-care reform becomes law. Less than half of Coakley's supporters say they or the state would be better off as a result.

Among Brown's supporters who say the health-care reform effort in Washington played an important role in their vote, the most frequently cited reasons were concerns about the process, including closed-door dealing and a lack of bipartisanship. Three in 10 highlighted these political maneuverings as the motivating factor; 22 percent expressed general opposition to reform or the current bill.